{"id":39558,"date":"2019-12-12T04:24:51","date_gmt":"2019-12-12T04:24:51","guid":{"rendered":"\/forum\/forums\/topic\/modal-analysis-reduction-of-natural-frequency\/"},"modified":"2019-12-12T04:24:51","modified_gmt":"2019-12-12T04:24:51","slug":"modal-analysis-reduction-of-natural-frequency","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/modal-analysis-reduction-of-natural-frequency\/","title":{"rendered":"Modal Analysis &#8211; reduction of natural frequency"},"content":{"rendered":"<p>Apologies I&#8217;m starting a second discussion but this forum has been really helpful.<\/p>\n<p><\/p>\n<p>In my model to reduce the natural frequency, I have added revolute joints to 2xsupports to allow DOF around pins bring my natural frequency down, although my frequency still needs to be lower (currently 6.8Hz to 3.5Hz). Model has been drawn to exact geometries. Additional mass to components is not an option as I have checked all components and they are correct mass properties. The supports are all set to fixed (2x torque arms &amp; 4x base plates) and since the structure is actually sitting on an upper mezzanine framework, I believe there would be some flexibility in the lower framework supporting the structure ( so maybe using different supports(elastic) with set stiffness representing the lower frame flexibility will reduce natural frequency. The only other thing I can think of is looking at my contact regions to reduce the natural frequency? Will this be effective in reducing natural frequency?&nbsp;<\/p>\n<p><\/p>\n<p>&nbsp;<\/p>\n<p><\/p>\n<p>Below is a screenshot of the model isometric and contact region pane.<\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/7cfab5ff-cdbd-4bd7-8d7d-ab1e01626916\/ede6e0dc-0f31-429e-87de-ab21004871a9_model.jpg?width=690&amp;upscale=false\" alt=\"\"><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/7cfab5ff-cdbd-4bd7-8d7d-ab1e01626916\/8b47a68f-395a-42d7-ab67-ab2100487ee0_model1.jpg?width=690&amp;upscale=false\" alt=\"\"><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/7cfab5ff-cdbd-4bd7-8d7d-ab1e01626916\/4b050fae-3988-4835-97a2-ab210048baad_tq.jpg?width=690&amp;upscale=false\" alt=\"\"><\/p>\n","protected":false},"template":"","class_list":["post-39558","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["11737"],"_bbp_old_topic_author_name_id":["Anonymous"],"_bbp_old_is_topic_anonymous_id":["false"],"_bbp_old_closed_status_id":["publish"],"_bbp_author_ip":[null],"_bbp_old_sticky_status_id":["normal"],"_bbp_likes_count":["0"],"_btv_view_count":["1532"],"_bbp_subscription":["245694"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["39558"],"_bbp_forum_id":["27791"],"_bbp_engagement":["240","171219","171357"],"_bbp_voice_count":["3"],"_bbp_reply_count":["7"],"_bbp_last_reply_id":["100850"],"_bbp_last_active_id":["100850"],"_bbp_last_active_time":["2019-12-15 23:07:32"]},"test":"rmaur29"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/39558","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/39558\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=39558"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}